The invention concerns a suction roller for the movement of sheet-shaped workpieces, particularly for their acceleration or braking.
These types of suction rollers are used, for example, to accelerate a sheet lifted from a stack to the speed of a downstream conveyor.
The invention has as its object the provision of a suction roller according to the generic portion with a simple design which can be produced economically and with efficient flow technology.
A wheel body having channels starting at one face which are open on at least one side and which rotate in sequence past a fixed suction nozzle positioned on one face, as well as a surrounding band applied to the external circumference of the wheel body with protrusions extending outward and indentations between them, with each indentation connected by means of at least one connection boring with a channel, are provided to achieve this object.
The wheel body advantageously consists of a hard plastic. This can easily be bored to produce the channels. The band is preferably implemented as a toothed belt which is manufactured from an elastic material. The toothed belt is then applied to the wheel body under tension. In this embodiment, special means for attachment of the toothed belt to the wheel body are no longer necessary. If a toothed belt is used, the teeth, which extend outward and are continuous over the width of the belt, provide protrusions, and the gaps between them provide indentations, in a very simple way. These indentations preferably run parallel to the axis, so that their entire width can be reliably covered by a sheet held on by suction.
According to a further embodiment of the invention, the protrusions of the band, preferably formed by the teeth of the toothed belt, have an approximately rectangular cross-section with an external surface having a good grip. In this way, a large contact surface for the workpieces to be accelerated can be achieved.
The wheel body advantageously consists of a hub part having an integral covering disk with a larger diameter on one face and a covering disk which can be put onto the other face of the hub part. In this way, the band preferably implemented as a toothed belt can be easily applied to the wheel body. This measure simultaneously closes the indentations of the band and/or toothed belt on the completely assembled suction roller laterally, so that stronger suction is achieved in the individual indentations.
A particularly simple embodiment results if the removable covering disk has an internal projection with a diameter corresponding to the diameter of the hub part and can be attached to the hub part by means of the elastic band preferably implemented as a toothed belt. In this way, the wheel body and the loose covering disk can be attached by means of the band and/or toothed belt in one single work step and additional attachment means can be dispensed with.
Further characteristics and advantages result from the following description of an exemplary embodiment with reference to the drawing.